9 research outputs found
Fast Diffusion Process in Quenched hcp Dilute Solid He-He Mixture
The study of phase structure of dilute He - He solid mixture of
different quality is performed by spin echo NMR technique. The diffusion
coefficient is determined for each coexistent phase. Two diffusion processes
are observed in rapidly quenched (non-equilibrium) hcp samples: the first
process has a diffusion coefficient corresponding to hcp phase, the second one
has huge diffusion coefficient corresponding to liquid phase. That is evidence
of liquid-like inclusions formation during fast crystal growing. It is
established that these inclusions disappear in equilibrium crystals after
careful annealing.Comment: 7 pages, 3 figures, QFS200
NMR Study of Disordered Inclusions in the Quenched Solid Helium
Phase structure of rapidly quenched solid helium samples is studied by the
NMR technique. The pulse NMR method is used for measurements of spin-lattice
and spin-spin relaxation times and spin diffusion coefficient
for all coexisting phases. It was found that quenched samples are two-phase
systems consisting of the hcp matrix and some inclusions which are
characterized by and values close to those in liquid phase. Such
liquid-like inclusions undergo a spontaneous transition to a new state with
anomalously short times. It is found that inclusions observed in both the
states disappear on careful annealing near the melting curve. It is assumed
that the liquid-like inclusions transform into a new state - a glass or a
crystal with a large number of dislocations. These disordered inclusions may be
responsible for the anomalous phenomena observed in supersolid region.Comment: 10 pages, 3 figure